Story highlights

Richard Matt and David Sweat are on the loose after breaking out of prison

They apparently used power tools, but it's not clear why guards apparently didn't hear

CNN  — 

Convicted killers Richard Matt and David Sweat pulled off the kind of prison break that would normally be fodder for movies – except theirs might be even more astonishing.

Armed with a complex plot and power tools, the pair did what no one else has been able to do in the 170-year history of New York state’s most populated prison: escape from its maximum security walls.

Now, as authorities look for the men in three countries, many are left scratching their heads.

Here’s what we know and don’t know about their scheme:

The tools

What we know: Matt and Sweat, who lived in adjacent cells, apparently used power tools to cut through a concrete-and-steel wall at the Clinton Correctional Facility in Dannemora, New York, authorities said.

What we don’t know: How in the world they got those power tools and how guards didn’t hear them being used.

New York Gov. Andrew Cuomo said the prison, built in 1845, undergoes regular maintenance, so it’s possible the tools came from workers who are often in the facility.

The company who employs the maintenance workers is cooperating with the investigation, New York State Police Maj. Charles Guess said.

The escape

What we know: After cutting through the steel walls of their cells, the two followed a catwalk “down an elaborate maze of pipes into tunnels and exited a series of tunnels at the manhole cover,” the governor said.

What we don’t know: How Matt and Sweat could have known the layout of the dark, complex labyrinth in the bowels of the prison well enough to make their way out.

The help

What we know: New York Gov. Andrew Cuomo told CNN the inmates must have had help in carrying out the plot. An employee at the prison is being questioned as a possible accomplice, a law enforcement source briefed on the investigation told CNN. The woman, who worked with the inmates tailoring clothing at the prison, knows the two “very well,” the source said. She has has not been charged or arrested.

What we don’t know: How did they get the power tools? How could they have known the layout of the bowels of the old prison? Did they have help from the inside? Cuomo said it was possible the tools came from contractors working on the 170-year-old prison. Authorities are also looking at civilian prison employees, he said. But he seemed to rule out the involvement of the prison’s certified employees. “I’d be shocked if a guard was involved, and that’s putting it mildly,” he said.

The freedom

What we know: The two men left only one message during their escape: A yellow note on a pipe that read, “Have a nice day!”

For Matt, this isn’t his first time escaping prison. In 1986, he escaped from an Erie County jail, the New York governor’s office said.

Upon his capture, Matt was sent to a maximum security prison in Elmira, New York, in 1986 on charges of escape and forgery. He was released from the Elmira Correctional Facility in May 1990.

What we don’t know: What the two men will do next.

“Because they’re stone-cold killers, you would expect them to stop at nothing to get out of the prison and to maintain their freedom once they are out,” CNN law enforcement analyst Tom Fuentes said.

“That means they could have invaded one of the local homes … killed the people, stole their car, and driven halfway across the United States by the time (authorities) even know they were gone. So the police are going to have to check for the well being of every resident in the town.”

CNN’s David Shortell and Monte Plott contributed to this report.